Oct 17 (Reuters) - Lendlease Group has sold a stake worth about A$450 million ($352 million) in its retirement living business to Dutch fund manager APG Asset Management N.V., and said it expects construction earnings to weaken next year.

The impact of the deal to sell a quarter of the retirement living business, including transaction costs, will be a net loss after tax of about A$35 million, the company said in a statement on Tuesday. The retirement living business had an overall book value of about A$1.8 billion as at June 30.

APG said the stake would help it get exposure to an asset seen as benefiting from Australia’s ageing population. Figures from the country’s 2016 census show an extra 84,000 people aged over 85 compared with 2011.

Lendlease will continue to manage the business under the Lendlease brand, with no change to its management team.

On construction, Lendlease said underperformance in the business is expected to hurt the company’s 2018 earnings, but did not disclose to what extent. Construction accounts for around 25 percent of the Australian developer’s earnings.

“We expect the strength of our diversified business model will offset the underperformance in our Australian construction business,” group Chief Executive Steve McCann said.

The company in August predicted a “strong” outlook for the construction division and the weakened forecast would likely weigh on the company’s shares on Wednesday, analysts said.

On Tuesday, Lendlease shares rose 0.4 percent to A$18.60, in a broader market that closed up 0.7 percent.

Lendlease also said it had established a joint venture with Japan’s Softbank Group Corp to develop and own telecom infrastructure assets in the United States, with the partners committing $200 million equity each to build telecommunications infrastructure across the U.S.

The venture will target $5 billion of telecom infrastructure assets over the medium term. ($1 = 1.2767 Australian dollars) (Reporting by Ambar Warrick in Bengaluru and Tom Westbrook in Sydney; Editing by Himani Sarkar)